Asphalt cutback, hard film rust preventive



2,872,334 Patented Feb. 3, 1959 ASPHALT CUTBACK, HARD FEM RUSTPREVENTIVE Michael J. Furey, Berkeley Heights, and Roy A. Westlund, Jr.,Roselle, N. J., assignors to Esso Research and Engineering Company, acorporation of Delaware No Drawing. Application February 2, 1956 SerialNo. 562,948

6 Claims. (Cl. 106-271) This invention relates to improved rustpreventive compositions and, more particularly, to improved compositionshaving utility as solvent-cutback, hard film rust reventives. Morespecifically, the invention relates to asphalt cutback rust preventivecompositions which have been improved in low temperature flakingtendency by inclusion therein of a minor proportion of amicrocrystalline wax.

Solvent-cutback, hard film rust preventives are known in the art Theseare cold-applied compounds used for (1) the protection of metals exposedto a variety of outdoor weather conditions and (2) any general purposepreservation where a dry-to-touch film is desired. These materialsgenerally contain an asphalt diluted with a petroleum solvent. Thecompounds are fluid in nature and may be applied to the metal surfacesto be protected by dipping, brushing or spraying. Upon evaporation ofthe solvent, a thin film, usually about 1 to 5 mils thick, remains onthe metal parts to serve as protection against weathering, corrosivefumes, and the like. In addition, the protective coating should not flowfrom surfaces at high temperatures nor flake at low temperatures. Whendesired, the thin film is easily removed from the metal surfaces by theapplication of solvents such as petroleum solvents and the like.

Asphalts made by vacuum or steam reduction or by reduction followed byoxidation are desirable as base materials for use in certainsolvent-cutback, hard film rust preventives because these asphalts havegood storage stability and drying characteristics, give excellentprotection, and are readily removed after exposure. They do, however,tend to be excessively brittle at low temperatures, and when cold givean undesirable degreeof flak- .ing or chipping from the metal surfacesbeing protected. This is particularly undesirable since the portionof-the metal surface exposed is thus available for rusting and corrosionto an even greater degree than completely unprotected surfaces.

It has now been found and forms the object ofthis invention that thisundesirable flaking tendency may be inhibited by the inclusion in thesesolvent-cutback, hard ifilm rust preventive compositions of a minoramount of a microcrystalline wax. This discovery is indeed striking whenit is considered that the microcrystalline wax per se is extremelybrittle and flakes "quite readily at the test temperatures.

The base material for the compositions'of this inven 'tion comprisesfrom 40 to 70% by weight of an asphalt and from 60 to 30% of .a solventtherefor. The asphalt may be selected from the group of straight reducedasphalts or asphalts prepared by vacuum reduction to a solid'flux with apenetration of less than 200 mm./1O

followed by oxidation, with the latter being preferred. Especiallypreferred are asphalts which are vacuum reduced to a penetration of lessthan 70 mm./ and then oxidized to a softening point betweenabout 160 and170 F. Asphalts prepared by oxidation of a liquid flux are not operable.

The solvent used in preparing the base material may be any of thewell-known petroleum solvents having flash points between about andabout F. and mid-boiling points ranging from about 300 to about 350 F.with a final boiling point below about 410 F. If it is desired, blendsof various solvents having FBP below about 410 F. may be used as thediluent for the asphaltic material.

In accordance with the concept of the instant invention, hard film,solvent-cutback rust preventive compositions were formulated from thefollowing components.

THE ASPHALT COMPONENT Several different asphalts were used in preparingblends in accordance with this invention.

Asphalt A This asphalt is a reduced asphalt made by the vacuum reductionof a Columbian crude. This material, a straight reduced asphalt, had asoftening point of about 146 F.

Asphalt B This asphalt was prepared by vacuum reduction of a Venezuelan(Lagunillas) crude to a liquid flux having a flash point of about 500 to505 F. This flux was then oxidized by air blowing at about 425 F. to asoftenin point of to 180 F.

Asphalt C This asphalt was prepared by vacuum reduction of a Venezuelan(Lagunillas) crude to a 500/505 F. flash point liquid flux followed byoxidation by air blowing at about 425 F. to a softening point of 220 to235 F.

Asphalt A fourth asphalt was prepared by vacuum reducing a Venezuelan(Lagunillas) crude to obtain a solid flux having a 20 to 30 penetrationat 77 F. This material was then air blown at about 425 F. to a softeningpoint of 160 to F.

Asphalt E A fifth asphalt was prepared by vacuum reducing a Venezuelan(Lagunillas) crude to a solid flux with a 41 to 60 penetration followedby air blowing at about 425 F. to a softening point of 160 to 170 F.

SOLVENTS In the composition two different solvents were used. Solvent Awas a highly refined virgin cut petroleum solvent from a low sulfurparafiinic crude having the following inspections:

Flash point (tag), F 105 Kauri-butanol number 38.0 Aniline point, F 12950 Percent off at 375 F 90 Final boiling point, F 405 Solvent B was anaromatic petroleum solvent having more than 95% aromatics and having thefollowing inspections:

Flash point, F 107 Initial boiling point, F 300 Percent off at 330 F 50Percent off at 350 F Final boiling point, F 370 MICROCRYSTALLINE WAX-The waxes used were microcrystalline waxes having a melting point above170 F. These waxes were prepared by conventional solvent dewaxing ofpetrolatums or by the solvent dewaxing of the residuum settling out ofcrude storage tanks. Inspections on these waxes are as follows:

Wax A Color (N. P. 'A.) 3 Flash point F 560 Fire point F 590 Viscosity210 F SSU 87 Acid No. (ASTM D-974) Saponification No. (ASTM D-94) 0Penetration (ASTM..D-) mm./ 4 M. P. (ASTM D-127) F 192 Wax B Color (N.P. A.) I. 2 /2 Flash point F 550 Fire Point F 610 Viscosity 210 F SSU113 Acid No. (ASTM D-974) 0 Saponification No. (ASTM D-94) O Penetration(ASTM D-5) mm./ l0 3 M. P. (ASTM D-127) F 193 Specific, gravity 60 F0.943

Operable Preferred Component Range (wt. Range (wt.

percent) percent) Asphalt 53. 0-63. 0 29. 34. 0-44. 0 Microwax 1.0-8.03. 0-5. 0

In accordance with the concept of the instant invention several blendswere prepared. These blends were submitted to the following standardtests for hard film rust preventive compositions.

(1) Film thickness.-This test is conducted as follows: A steel testpanel, 2 x 4" x 4;", is finished by polishing with 240 grit aluminumoxide abrasive with cloth or paper backing to a surface finish of 10-20micro inches (root means square). The panel is then wiped clean andrinsed in boiling naphtha, then in boiling methanol and allowed to coolin a desicator to 77i2 F. The panel is weighed and then immersed for oneminute in the test compound maintained at 77i2 F. The panel is withdrawnat the rate of 4 inches per minute and hung to dry in the laboratory.After 24 hours drying the panel 4 is reweighed and the film thicknesscalculated by the specific gravity weight method.

(2) Drying time.--This test is conducted as follows:

A test panel is coated as in the film thickness test and allowed to hangin the laboratory for 4 hours. At the end of this time the panel ishandled, using normal finger pressures. Any transfer of the compound orinjury to the film fromhandling fails this test.

(3) Salt'spray test.This test is conducted as follows:

Steel test panels are prepared and coated as in the film thickness testand dried for 24 hours in the laboratory. The panels are then placed ina salt spray cabinet conforming to Method 4001.1 of FederalSpecification VV-L-791E and exposed for 14 days. At the end of this timethe panels are removed, cleaned with solvent, and examined for rust. Anypanel showing no more than 3 corrosion spots, no one of which is largerthan 1 mm. in diameter, passes this test. Corrosion within A" of thepanel edges is not considered in this evaluation.

(4) Weather-O-Meter test.-This testis conducted as follows:

Steel test panels are coated and dried as for the salt spray test. Theyare then exposed to the test described in Method 615.1'of SpecificationTT-P-141 for 1200 hours. At the conclusion of the test the coating isremoved and the panel examined for signs of-rust. Corrosion within A ofthe panel edge shall be disregarded. Any panel showingno more than 3corrosion spots, no one of which is larger than 1 mm. in diameter,passes the. test.

(5) Low temperature adhesion test.This test is conducted as follows:

- Panels are coated as in the film thickness test and dried for 24hours. The panel is then cooled to 0 F. for one hour and 4 parallelscratches approximately A5" apart and one inch long made on the filmwith the scratch tool. Four similar scratches shall be madeperpendicular to the first four. Chipping of the coating extending morethan 19, from either side of the scratch marks shall be considered afailure. The scratch tool consists of four razor blades held paralleland /e apart by a metal holder.

(6) Thirty-day storage test-This test is conducted as follows:

Steel panels are coated'and film thickness measured as in the first testabove. The compound is then stored in the laboratory at 77i5 Fffor 30days. At the end of this time the compound is mixed by rolling a tightlysealed 0.9 full can at approximately R. P. M. for 5 minutes. A secondset of panels are then coated as before and the film thickness measured.Any increase in film thickness exceeding 15% fails the storage test.

In Table I below, there is set out the composition of these blends andthe test results.

TABLE I.HARD FILM SOLVENT OUTBACK RUST PREVENTIVES Blend No Composition(wt. percent) Asphaltic Material:

Asphalt A (146 F. S. P.) Asphalt B F.I180 F. S. P.) Asphalt 0 (220F./235 F. S. P.) Asphalt D (160 F./ F. S. P.) (from Solvent:

- Solvent A (405 F. FBP) Solvent B (370 F. FBP) can Microwax:

Wax A Wax B Test Results:

Film Thickness (mils) Drying Time (4 hours) Salt Spray (14 days)Weather-O-Meter (1,200 hrs.) Low Temp. Adhesion-flaking (in.). ThirtyDay Storage 3. 0 Pass Pass 6 Pass 3. 0 Pass Pass Pass 3. 0 Pass PassPass .4. 0 Pass Pass '3. 0 Pass Pass Pass 4. 0 Pass Pass Pass 2 PassPass %2 Pass 7 it 2 2 Pass Pass Pass A careful examination of the dataset out in Table I shows the outstanding advantages of the blendsprepared in accordance with the inventive concept. It is to be seen thatthe inclusion of from 3 to 5% of a microcrystalline wax is essential toenable the rust preventive to pass all the tests set out above. Inaddition, the asphalt must be either a straight reduced asphalt (A) orone prepared by oxidation of a solid flux prepared by reduction (D orE). Addition of the microcrystalline Wax to asphalts prepared byoxidation of liquid fluxes (B or C) gives unsatisfactory products.

One outstanding composition prepared in accordance with the inventiveconcept has the following components.

55.0 wt. percent reduced and oxidized asphalt (160/ 170 F. S. P.) 36%solvent A 5% solvent B 4% wax A p This composition was tested accordingto Military Specification MIL-C-16173-A, grade I for solvent cutbackrust reventives, hard film. Results of these tests are set out in TableH below:

TABLE II.SPECIFIOATION MIL-O-16173-A TESTS Test Blend Flash Point (100F. Min.) Pass Removablllty after Exposure Pass Film Thickness (4.0 Mil.Max.) 3. Salt Spray, 14 Day Pass Accelerated Weathering, 1,200 HoursPass Recovery From Low Temperature..- Pass Sprayahllity 40 F Pass LowTemperature Adhesion (0 Pass Drying Time, 4 Hours Pass Solvent. (410 F.Max. End Point)-.. Pass Corr i n Pass ALLOWABLE LIMITS Immersion:

=l=1.0 rug/cm. 0. 03 =|=5.0 mgJem. 0.00 =|:7.5 lug/em. 0. 01 :l:0.5!.'|1,g./c1'n. 0. 01 Aluminum i0.2 rug/cm. -0.02 S el =|=0.2n1g./cm.0.02 Coating =!=1.0 mg./cm. 0.00 =l=5.0 mg./cm. +0.11 Zinc =a7.5 na ems0.00 Magnesium" 5:0.5 mg./om. +0.02 Aluminum... =|=0.2 mg./cm. 0. 00Steel 5:02 mgJcmfi. +0.02

It is to be seen that this composition was quite satisfactory in allportions of this test.

To summarize briefly, the instant invention relates to hard film solventcutback rust preventive compositions. Compositions of the inventioncomprise from 40.0 to

70.0 wt. percent, preferably from 53% to 63% of a reduced. or a reducedand oxidized asphalt having a softening point between 140 and 250 F.,preferably between 160 to 170 F., from about 29.0 to about 59.0 wt.percent of a solvent having a final boiling point of within the range offrom 350 to 450 F, preferably from 34.0 to 44.0 wt. percent of a solventhaving a final boiling point between about 360 and 410 F., and about 1.0to 8.0 wt. percent, preferably about 3.0 to 5.0 wt. percent, of amicrocrystalline Wax having a melting point above about 175 F. and apenetration of less than 10 mm./l0.

What is claimed is:

1. A solvent cutback hard film rust preventive composition whichconsists essentially of a blend of from about 53% to about 63% of anasphalt selected from the class consisting of straight reduced asphaltshaving a softening point of from about F. to about 250 F. and asphaltsprepared by reduction to a solid flux having a penetration of less than200 mm./ 10 at 77 F. followed by oxidation to a softening point of fromabout 140 F. to about 250 F., about 34% to about 44% of a petroleumsolvent having a final boiling point within the range of from 350 to 450F., and about 3% to about 5% of a microcrystalline wax having a meltingpoint above 175 F. and a penetration at 77 F. less than 10 mm./ 10, saidpercentages being by weight based on the weight of the totalcomposition.

2. A rust preventive composition according to claim 1 wherein saidasphalt is a reduced and oxidized asphalt.

3. A rust preventive composition according to claim 1 wherein saidsolvent has .a final boiling point of between 360 and 410 F.

4. A rust preventive composition according to claim 1 wherein saidasphalt is a reduced asphalt.

5. A solvent cutback hard film rust preventive composition whichconsists essentially of a blend of about 53% to about 63% of an asphaltprepared by reduction to a solid fiux having a penetration at 77 F. ofless than 70 mum/10 followed by oxidation to a softening point of aboutto F., about 34% to about 44% by Weight of a petroleum solvent having afinal boiling point within the range of about 360 to about 410 F., andabout 3.0 to 5.0 wt. percent of a microcrystalline wax having a meltingpoint above F. and a penetration at 77 P. less than 10 mm./10.

6. A solvent cutback hard film rust preventive comlposition whichconsists essentially of a blend of about 55.0 wt. percent of an asphaltprepared by reduction to a solid flux having a penetration at 77 F. ofless than 70 mm./ 10 followed by oxidation to a softening point of about160 to about 170 F., about 41.0 wt. percent of a petroleum solventhaving a final boiling point of about 405 F., and about 4.0 wt. percentof a microcrystalline wax having a melting point above 175 F. and apenetration at 77 F. less than 10 mm./10.

References Qited in the file of this patent UNITED STATES PATENTSSchiermeier et al Nov. 6, 1951

1. A SOLVENT CUTBACK HARD FILM RUST PREVENTIVE COMPOSITION WHICHCONSISTS ESSENTIALLY OF A BLEND OF FROM ABOUT 53% TO ABOUT 63% OF ANASPHALT SELECTED FROM THE CLASS CONSISTING OF STRAIGHT REDUCED ASPHALTSHAVING A SOFTENING POINT OF FROM ABOUT 140*F. TO ABOUT 250*F. ANDASPHALTS PREPARED BY REDUCTION TO A SOLID FLUX HAVING A PENETRATION OFLESS THAN 200 MM./10 AT 77*F FOLLOWED BY OXIDATION TO A SOFTENING POINTOF FROM ABOUT 140*F TO ABOUT 250* F., ABOUT 34% TO ABOUT 44% OF APETROLEUM SOLVENT HAVING A FINAL BOILING POINT WITHIN THE RANGE OF FROM350* TO 450*F., AND BOUT 3% TO ABOUT 5% OF A MICROCYSTALLINE WAS HAVINGA MELTING POINT ABOVE 175*F. AND A PENERTRATION AT 77*F. LESS THAN 10MM./10, SAID PERCENTAGE BEING BY WEIGHT BASED ON THE WEIGHT OF THE TOTALCOMPOSITION.